We have talked about pistol-caliber carbines before. They are light, fun to shoot, more accurate than a handgun of the same caliber, and give your favorite cartridge a little extra velocity, too.

But how MUCH extra velocity? Lots of estimates get thrown around, but not a lot of hard #s. And how accurate are the factory specs, anyway?

Well here they are.

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I started with .40S&W, since I had ready access to a pistol and carbine chambered for the round. 9mm is coming soon!

Since I had 5 different types of factory ammo, from 2 brands, I decided to test them all. As I get more ammo, I will test that too.

I tested using a Glock 23 (which has a 4″ barrel) and a Ruger PC4 (which has a 16.25″ barrel). I set up the chronograph, and put 10 rounds of a particular ammo through the pistol, then repeated the process (same ammo) with the carbine. I cleaned the chrony sensors with canned air between strings.

Here are the results, from heavy bullets to lighter ones:

Magtech 180gr FMC

That’s pretty close to Magtech’s factory spec, and since the test gun probably had a barrel longer than 4″, the lower velocity is understandable. (Magtech’s site did not specify what barrel length was used to test, nor whether it was an actual gun or a test barrel.)

Federal HydraShok 180gr

That’s quite a decrease from factory spec, even allowing for a 4″ barrel. (Surprisingly, Federal did not supply barrel length or if it was a test barrel for any of their .40S&W factory ballistics). And that muzzle energy is barely above what Federal’s 9mm selections offer:

Federal HydraShok 124gr, 147gr, 135gr

On to the next selection:

American Eagle (Federal) 165gr FMJ

This was a serious deficit compared to the factory spec. It took the carbine-length barrel to approach the quoted ballistics! Yeah, it’s not a defensive round, but the fact that a major manufacturer is wrong on their #s is troubling. Maybe it was a bad batch? I haven’t seen any notice about it, and I actively look for such notices.

Federal HydraShok 165gr

This is actually higher velocity & energy than the factory #s, and a longer barrel would be higher still. But, once again, the muzzle energy is only marginally better than Federal’s 9mm offerings (see above).

Federal HydraShok 155gr

The lightest bullet of the bunch delivered the highest muzzle energy & velocity. It wasn’t as good as the factory specs (the shorter barrel is probably to blame for some of that). But this round offers the only significant upgrade from 9mm energy levels. And in the carbine, it offers much more.

But, on the subject of pistol caliber ammunition in carbines, the increase in velocity from the longer barrel was 114-156fps. That’s less than I would have guessed, and certainly less than the “200-250fps” that I have heard. Maybe these .40 rounds are really efficient?

I am troubled that 3 of the 4 Federal rounds were significantly lower velocity than quoted.

I have some Hornady ammo to test next, and I will get some others too. But for the moment, the 155gr HydraShok is going to be what I fill my pistol magazines with. I will use the others for the carbine.

Mike, I think there is still some testing to be done before we go as far as swapping barrels. I think we have all pointed out a few issue to correct to help solidify some of these results. I’m betting the answer is somewhere, and should be pretty good.Story time…I took a Marlin 336 .30-30 of my co-worker who thought his scope was bad. I took some factory Hornady 160FTX and was lucky to get <3MOA and generally 3-4MOA at 100 yards. Maybe it was his scope. Playing with some slightly lower charges came up with 32.0gr of the Hodgdon LEVERevolution that put itself into 3/8″ 5-round. Yeah he lost about 200-250FPS in velocity compared to factory, but at ranges that he’ll use his .30-30, I don’t think the deer is going to care.Looking at Knightstalkers results here he had about 1MOA with his first H4895 load, but his other loads with that powder were in .8gr higher intervals, and for all we know his node is a tad below instead of high. I think it’s best to take his best group, and try to pinpoint where his node really is. No offense to Knightstalker here, but his approach to load testing was a shotgun attempt to find something. In all fairness he was using “recommended loads”, but we all know not all rifles are built the same, and recommended doesn’t always mean best. We are also only looking for 300-yards for his 3-gun, so like that Marlin, it isn’t vital if we lose just a tad bit of velocity to get his accuracy.***EDIT*** Mike brought up an excellent point though with a free-floated fore-end. This would be a wise investment indeed for peak performance.

That would be an INDIVIDUAL right…

A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.